The long-term goal of this research is to investigate the reasons for lack of compliance with medical regimens in a rural Native American population with a high incidence of type II diabetes mellitus, so that diabetes- associated morbidity and mortality may be decreased. To address that issue, this pilot study will compare the cognitive function of two groups of older rural Native Americans: those with and without type II diabetes mellitus, to determine whether type II diabetes is associated with decreased cognitive function. In people isolated from health care, cognitive dysfunction may lead to an inability to follow treatment plans, maintain self-care, and determine appropriately when to seek health care, all of which may lead to poorer outcomes. The specific aims are (1) to develop and administer a tool to assess cognitive function in an older population of Native Americans, and (2) to determine if type II diabetes mellitus is related to a diminished level of cognitive function. Participants, community-dwelling elders aged 45 to 74 years, will be identified for each group from one reservation within the Aberdeen Area of the Indian Health Service in South Dakota. They will be interviewed to obtain measures of psychobehavioral function; information about demographic and socioeconomic variables, other risk factors for cognitive alteration, and diabetes history (in the diabetic group); and hematologic measures of glucose control. Medical record review will be conducted to validate this data and to obtain additional information about the history of chronic illnesses and conditions and recent physiological parameters. Comparisons between and within the two groups will be made using correlation, multiple regression analysis, multivariate analysis of variance, and analysis of covariance techniques.